A federal judge in Washington, D.C., ordered the Trump administration on Wednesday to stop the expulsion of migrant children who cross the border alone — a policy enabled by a March emergency order by the Centers for Disease Control because of the coronavirus pandemic.

Why it matters: As of September, nearly 9,000 unaccompanied migrant children had been expelled because of the CDC order.

What they're saying: "Today’s ruling is a critical step in halting the Trump administration’s unprecedented and illegal attempt to expel children under the thin guise of public health," ACLU's Lee Gelernt, the lead attorney in the case, said in a statement.

• "The administration’s order has already allowed for the rapid expulsion of more than 13,000 children in need of protection, who were legally entitled to apply for asylum."

The big picture: Thousands of migrant children, families and adults from different countries have been sent to Mexico, at times violating a diplomatic agreement with Mexico, the New York Times Caitlin Dickerson reported.

• More than 197,00 migrants have been quickly expelled after reaching the border because of the CDC's emergency order, according to CBP data.
• Before the March order, unaccompanied migrant minors were required to be put in the care of the Office of Refugee Resettlement, which oversees a network of child migrant shelters and seeks to release migrant children to family members or other sponsors who are already in the U.S.